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Mohamad Khajavi
Mohamad Khajavi

Posted on • Edited on

Env Variables in k6

#k6 #testing #cli

Hey Devs πŸ‘‹πŸ»

We always have some .env files in our projects to assign the environment variables.

Now as mentioned here, we can pass the env vars like:

k6 run -e MY_NAME=MoKhajavi75 script.js
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And use them in our k6 project like:

export default function () { console.log(__ENV.MY_NAME); }
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This works if the env variables are not too many.

But what if we have many? Or even if we don't want to pass them via CLI and use a .env file πŸ€”

I have a nice yet effective bash script to assign those env vars from a .env file:

#!/bin/bash ENV_FILE_PATH=".env" ENV_VARS=() if [[ ! -f "${ENV_FILE_PATH}" ]]; then echo "\"${ENV_FILE_PATH}\" file not found!" exit 1 fi while IFS= read -r line; do key=${line%%=*} value=${line#*=} ENV_VARS+=("-e" "${key}=${!key:-${value}}") done < <(grep -vE '^\s*($|#)' "${ENV_FILE_PATH}") exec k6 run "${ENV_VARS[@]}" "$@"
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This script skips comment lines (the ones starting with "#" and empty lines) so feel free to write your .env file as you like, as many variables you like!

We can name it run.sh and use it like:

./run.sh script.js
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Just don't forget to make it executable! (chmod +x run.sh)

Now, what about the usage part? What if we're using TypeScript, as it's getting into k6?

Let's write a nice getEnv utility function too:

type EnvVars = 'KEY1' | 'KEY2' | 'KEY3'; /** * Retrieves environment variables. * @param key - The key of the environment variable to retrieve. * @returns - The value of the environment variable. * @throws {Error} - Throws an error if the environment variable is not set. * @example * const value = getEnv('KEY'); */ export const getEnv = (key: EnvVars): string => { const env = __ENV[key]; if (env === undefined) throw new Error(`Environment variable ${key} is not set`); return env; };
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So we can improve the above example:

import { getEnv } from './env'; export default function () { console.log(getEnv('MY_NAME')); }
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This way, it suggests code intellisense and we have a nice, well-documented utility function for usage too.

Hope this helps :)
Feel free to comment with any questions or suggestions!

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